The next wave for the network management and wireless development, such as WiFi to WiMax and 3G to 4G, is to integrate the wired and wireless networks to form as fixed-mobile convergence (FMC) network environment for offering more services. The FMC coupled with IP multimedia subsystem (IMS) is also a trend for voice, video, data and mobility service. In other words, the widespread network industry is moving towards the portable and conventional devices equipped with network interfaces to provide people with more service options anywhere and anytime.
Multimedia streaming service is a key application on FMC network. Real-Time Streaming Protocol (RTSP)/Real-Time Protocol (RTP) are typical protocols for linear video stream and. HyperText Transfer Protocol (HTTP) is a typical protocol for non-linear video stream. However, due to the mobility requirement, the ongoing session may be interrupted during handoff across networks or session migration across devices.
Two cases are often considered on how to keep ongoing session continuous. One is the issue of inter-interface or inter-network handoff, and the other is the issue of inter-device session migration. Many approaches have been developed. For example, WO0131472 disclosed a mobility management protocol targeting at 3G-IP environment to support the real time and non-real time multimedia application on mobile device. The patent document disclosed a technique supporting SIP-based applications, but does not provide a complete mobility management solution for non-SIP-based multimedia applications.
U.S. Patent Publication No. 2007/0171895 disclosed a method for seamless handover to roaming terminal for multimedia stream session. As shown in FIG. 1, moving caller 104, such as a user agent client, is attached to the current domain A through an interface element 103. Mediating network element 110 on communication network 100 is comprised in a communication path of a server 105, such as user agent server, connecting to remote domain 115, to ensure the security of session ID, such as digital signature, or the encoding method of the multimedia stream so as to allow server 105 for identification.
Then, mediating network element 110 monitors the address change of the roaming terminal in the media overlay level of the multimedia stream session, and redirects the multimedia stream to updated address. Then, another mediating network element 120 at the control layer is used to replace mediating network element 110. In this manner, moving caller 104 is switched to a different domain B. The patent publication document disclosed a technique utilizing mediating network element to support mobility management for multimedia applications.
Two types of media formats are mainly used in the transmission of streaming service. FIG. 2 shows an exemplary schematic view of comparing these two formats. As shown in FIG. 2, the left side of the figure is metadata-spreading format. In other words, the metadata with metadata-spreading format is spread all over the entire file, and the media data is also spread all over the entire file. Each pair of the metadata and media data is recorded chronically. This type of media format may be used to transmit a linear multimedia stream, and usually uses RTSP/RTP as transmission protocol. The right side of the figure is metadata-gathering. In other words, all the metadata is gathered in a metadata block 210, and all the media data is gathered in a media data block 220. This type of media format may be used to transmit a non-linear multimedia stream and usually uses HTTP as transmission protocol.
The conventional techniques may only solve a part of mobility management problems of the metadata-spreading multimedia streaming. Therefore, it is imperative to devise a new mechanism applicable to splicing session of non-linear multimedia stream in addition to splicing session of linear multimedia stream so that the mobile multimedia streams with metadata-spreading or metadata-gathering format may keep ongoing session continuous.